Synanthropic primary hosts carrying viruses may burden new dangers for humanity. The SARS-CoV-2 virus causing the COVID-19 pandemic presently infected near 2 million humans. Virus characteristics resulted in a successful outbreak due to various reasons: (i) patient are infectious before experiencing symptoms; (ii) carrying hosts might be symptomless, disease outcome in ill patients depends on underlying conditions, age and sex; (iii) intermediate hosts, acting as reservoirs living close contact with humans (e.g., livestock, pets); (iv) possible virus mutations from animal/person to person/person transmission; (v) the virus can spread through the air; (vi) the half-life of the virus is long, reaching some days, thus feces and street dust increase the hazard, and contact spread is also turned into critical.